In a manufacturing facility, various chemicals in gaseous and liquid form are used in various fabrication processes. For instance, in a semiconductor fabrication plant, a semi-conducting substrate must be processed in a multiplicity of manufacturing steps, i.e., as many as several hundred in order to complete an integrated circuit chip. The multiplicity of manufacturing steps may include cleaning, cooling, deposition, etching and any other necessary processing steps. A variety of chemicals, including liquids and gases must be used in these steps. For instance, to clean or cool a process chamber or a wafer platform, to etch a specific feature on a substrate, to clean after each etching or deposition steps, to deposit layers of materials on a substrate, or to carry out any other processes.
The variety of chemicals used in a semiconductor facility must be handled with care since some of the processing chemicals are highly toxic and/or highly corrosive. For instance, strong acids are frequently used in an etcher for the etching of metals for forming a conductive path. Since hazardous materials are not always all consumed in chemical processes, unused hazardous chemicals must be recycled or otherwise disposed of. Due to their hazardous nature, the materials must be carefully handled during their storage and transportation to avoid personal injuries and potential fire hazard. The mechanical components used in transporting these materials should therefore be minimized such that potential exposure of personnel to the chemicals may be reduced.
In a modern semiconductor fabrication plant, the fabrication process for an IC chip is carried out in a clean room atmosphere which is very tightly controlled to avoid any possibility of contamination. The floor space in a clean room is therefore very valuable considering the large number of processing equipment that must be utilized in fabricating an IC chip. There is a great incentive in reducing the floor space occupied by the processing equipment and any auxiliary equipment such as conduits connecting between the processing equipment and chemical storage facilities.
In transporting chemicals in a semiconductor fabrication facility, a number of check valves, or one-way valves are used in conduits in order to prevent possible back-flow of the chemical and possible contamination of the chemical storage tank reservoir. In transporting chemicals of either a liquid or a gas, a strainer or filter is frequently used in the conduit for straining or filtering out solid residues or other contaminants which may be present in the liquid or gas. For instance, in transporting a cooling water to a process machine, a large diameter, i.e., between 5 cm and 20 cm conduit is normally used. Since the water supply line may run a length of at least 50 or 60 cm, at least one-way valve and strainer-filter may be required to ensure a supply of clean cooling water to the process machine. The floor space occupied by the at least one one-way valve and strainer-filter may be significant.
It is therefore an object of the present invention to provide check valves and strainer-filters for use in a semiconductor fabrication facility that are compact in size, occupy a minimum floor space for installation, and present a low probability of fluid leakage.
It is another object of the present invention to provide an integrated check valve/strainer-filter assembly that combines the functions of a one-way valve and a strainer-filter in a single compact unit.
It is a further object of the present invention to provide an integrated check valve/strainer-filter assembly wherein a check valve and a strainer-filter are mounted together in a single compact unit with the strainer-filter housing being removable for cleaning or replacement of a filter element.
It is another further object of the present invention to provide an integrated check valve/strainer-filter assembly wherein a strainer-filter housing is mounted to an elongated conduit containing a check valve perpendicularly to a longitudinal axis of the conduit.
It is still another object of the present invention to provide an integrated check valve/strainer-filter assembly that is equipped with a flanged opening which can be opened for cleaning or servicing the strainer-filter element.
It is yet another object of the present invention to provide an integrated one-way valve/filter assembly for conveying and filtering a fluid flowing therethrough consisting of an elongated conduit, a filter housing removably mounted to the conduit and a one-way valve mounted in a fluid passage in the conduit.
It is still another further object of the present invention to provide an integrated one-way valve/filter assembly for conveying and filtering a fluid flowing therethrough wherein the filter housing is removably joined to the conduit for allowing the housing to be removed for service.
It is yet another further object of the present invention to provide an integrated one-way valve/filter assembly for conveying and filtering a fluid flowing therethrough which further includes an opening in the conduit for providing an access to the filter and a cover for sealingly engaging the opening.